1. Field of the Invention
Embodiments of the present invention relate to pumps, in particular to pumps for pumping hydraulic well control fluid into a production flowline of a well.
2. Description of the Prior Art
During the operation of a subsea well, hydraulic fluid is expelled from hydraulic control actuating devices, such as valve and choke actuators. Typically, in the past, this fluid has been exhausted to the sea. The fluid is, typically, ethylene glycol based and is now considered to be a pollutant. Environmental legislation now prompts well operators to stop exhausting such fluids into the sea, particularly on new installations, which presents well equipment suppliers with the problem of finding a solution to the new requirements. GB Patent Application No. 0820326.7 discloses a method of disposing of hydraulic well control fluid, comprising pumping the fluid into a production flowline of the well. Although it is possible to effect such a method with an electrically powered pump, a failure of electric power would not allow hydraulic fluid to continue to be exhausted from actuators during the well shut down. Embodiments of the present invention enables a pump that provides the necessary pressure to inject exhausted hydraulic fluid into the production flowline, handles the fluid exhausted during a well shut down and does not need electric power.